Cow Milk Risk Factors Associated With Bacterial Contaminations Along Dairy Value Chain in Lushoto and Handeni...

Milk and milk products are of high nutritional value but mishandling of any kind along the value chain leads to contaminations that shorten shelf life and pose public health threats.

To assess the milk handling practices, bacterial contaminations and determine selected milk-borne zoonotic pathogens along the dairy value chain in 14 villages.

A cross-sectional study was conducted in Lushoto and Handeni districts whereby 93 randomly selected respondents constituting farmers, vendors and restaurants/kiosks were interviewed and subsequently 166 milk samples were collected for microbiological enumeration and ascertain contaminations by Escherichia coli O157:H7 and Brucella abortus using standard protocols. Chi-square (χ²) and confidence intervals were used to compare proportions of risk factors for milk microbial contaminations; a probability of p < 0.05 was statistically significant. Logistic regression was used to assess the significant risk factors associated with milk microbial contaminations.

It was established that milking and milk storage was done under unhygienic conditions. Up to 92.1% of farmers had no training on livestock husbandry and milk handling practices. Mean bacterial counts in milk ranged between 3.3 and 5.8 log₁₀, which is in line with the East African Standards (5.3 log10 cfu/mL). However, 87% and 93% of milk from farmers and vendors, respectively, had bacteria count above the recommended EAC standards of 2.0 × 10⁵ cfu/mL implying poor microbiological quality. All milk samples had coliform plate count above EAC standards of 4.5 log CFU/mL. The mean bacterial count of 5.3 log10 cfu/mL was recorded with more counts in milk from vendors (4.6 to 6.1 log10 cfu/mL). Average levels of contamination in raw and pasteurised milk were not significantly different (p > 0.05). Factors related to hygienic practices of farmers along the milk production chain had no significant differences (p > 0.05) in microbial contamination. There was no E. coli O157:H7 contamination in milk, nonetheless B. abortus was detected in 37 out of 87 samples tested (42.5%) mostly from farmers.

Limited extension services, unhygienic practices along milk value chain contributed to high microbial contamination. Detection of B. abortus in milk is of public health significance due to its zoonotic potential. Therefore, the government and milk stakeholders should strengthen public and private livestock extension services for proper animal husbandry practices, improved milk value chain and control of zoonotic diseases.